Targeted delivery of a designed sTRAIL mutant results in superior apoptotic activity towards EGFR-positive tumor cells

Previously, we have shown that epidermal growth factor receptor (EGFR)-selective delivery of soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL), by genetic fusion to antibody fragment scFv425, enhances the tumor-selective pro-apoptotic activity of sTRAIL. Insight into the respective contribution of the agonistic receptors TRAIL-R1 and TRAIL-R2 to TRAIL-induced apoptosis may provide a rational approach to further optimize TRAIL-based therapy. Recently, this issue has been investigated using sTRAIL mutants designed to selectively bind to either receptor. However, the relative contribution of the respective TRAIL receptors, in particular TRAIL-R1, in TRAIL signaling is still unresolved. Here, we fused scFv425 to designed sTRAIL mutant sTRAILmR1–5, reported to selectively activate TRAIL-R1, and investigated the therapeutic apoptotic activity of this novel fusion protein. EGFR-specific binding of scFv425:sTRAILmR1–5 potently induced apoptosis, which was superior to the apoptotic activity of scFv425:sTRAIL-wt and a nontargeted MOCK-scFv:sTRAILmR1–5. During cotreatment with cisplatin or the histone deacetylase inhibitor valproic acid, scFv425:sTRAILmR1–5 retained its superior pro-apoptotic activity compared to scFv425:sTRAIL-wt. However, in catching-type Enzyme-Linked ImmunoSorbent Assays with TRAIL-R1:Fc and TRAIL-R2:Fc, scFv425:sTRAILmR1–5 was found to not only bind to TRAIL-R1 but also to TRAIL-R2. Binding to TRAIL-R2 also had functional consequences because the apoptotic activity of scFv425:sTRAILmR1–5 was strongly inhibited by a TRAIL-R2 blocking monoclonal antibody. Moreover, scFv425:sTRAILmR1–5 retained apoptotic activity upon selective knockdown of TRAIL-R1 using small inhibitory RNA. Collectively, these data indicate that both agonistic TRAIL receptors are functionally involved in TRAIL signaling by scFv425:sTRAILmR1–5 in solid tumor cells. Moreover, the superior target cell-restricted apoptotic activity of scFv425:sTRAILmR1–5 indicates its therapeutic potential for EGFR-positive solid tumors

Targeted apoptosis induction in hemato-oncology

The studies described in this thesis aim to selectively target and eliminate the malignant cell types as present in various forms of leukemia’s and lymphoma’s. To this end, we developed and pre-clinically assessed a series of novel recombinant fusion proteins in which a leukemia-selective scFv antibody fragment is genetically fused to soluble forms of the pro-apoptotic death ligands TRAIL or FasL. The various scFv:death ligand fusion proteins described were all designed to induce apoptosis by cross-linking of agonistic death receptors on tumor cells only after their specific binding to a predefined leukemiaassociated cell surface antigen. The data presented indicate that this approach appears to be highly efficient in eliminating cell lines as well as patient-derived tumor samples derived from several forms of leukemia’s and lymphoma’s. Zie: Chapter 9

Residual Venous Obstruction as an Indicator of Clinical Outcomes following Deep Vein Thrombosis: A Management Study

Residual venous obstruction (RVO) is considered a risk factor of recurrence and possibly other clinical outcomes following deep vein thrombosis (DVT). Current guidelines do not support an RVO-tailored duration of anticoagulant therapy; contemporary data of such management strategies are scarce. We aimed to evaluate an RVO-based management strategy and to assess associations of RVO with recurrence, post-thrombotic syndrome (PTS), arterial events and cancer. To gain further insight, D-dimer levels were measured one month after stopping anticoagulant therapy. Consecutive patients with symptomatic, proximal DVT were treated in a two-year clinical care pathway (CCP) at Maastricht University Medical Center and were followed up to 5 years. RVO was assessed at the end of regular duration of anticoagulant therapy, which was extended once if RVO was detected. The study was approved by the medical ethics committee. From a total of 825 patients, 804 patients (97.5%) completed the CCP and 755 (93.9%) were available for extended follow-up. Most patients (76.5%) stopped anticoagulant therapy. Incidence rates of recurrence, PTS, arterial events and cancer were 4.4, 11.9, 1.7 and 1.8 per 100 patient-years, respectively. RVO was independently associated with PTS (HR 1.66 [1.19-2.32]) and arterial events (HR 2.07 [1.18-3.65]), but not with recurrence or cancer. High D-dimer was associated with recurrence (HR 3.51 [2.24-5.48]). Our RVO-based management strategy might have attenuated the association of RVO with recurrence. In addition, RVO identified patients at increased risk of PTS and arterial events, which might be used to identify patients in need of alternative treatment strategies

Rivaroxaban plus aspirin for the prevention of ischaemic events in patients with cardiovascular disease:a cost-effectiveness study

Background Dual pathway inhibition with 2.5 mg rivaroxaban twice daily plus 100 mg aspirin once daily may be a promising alternative to 100 mg aspirin antiplatelet therapy for the prevention of cardiovascular events in patients with coronary artery disease and/or peripheral arterial disease. However, treatment costs and bleeding risks are higher, and there is another treatment option for peripheral arterial disease, 75 mg clopidogrel. A comprehensive assessment of benefits, risks and costs of dual pathway inhibition versus standard of care is needed. Methods We used a state transition model including cardiovascular, ischaemic limb and bleeding events to compare dual pathway inhibition to aspirin antiplatelet therapy in coronary artery disease, and additionally to clopidogrel antiplatelet therapy in peripheral arterial disease patients. We calculated the incremental cost-effectiveness ratio from costs and quality-adjusted life-years of lifelong treatment, and the cost-effectiveness probability at a euro50,000/quality-adjusted life-year threshold. Results Quality-adjusted life-years and costs of dual pathway inhibition were highest, the incremental cost-effectiveness ratios versus aspirin were euro32,109 in coronary artery disease and euro26,381 in peripheral arterial disease patients, with 92% and 56% cost-effectiveness probability, respectively (clopidogrel was extendedly dominated). Incremental cost-effectiveness ratios were below euro20,000 in comorbid peripheral arterial disease patients and coronary artery disease patients younger than 65 years, incremental cost-effectiveness ratios were above euro50,000 in carotid artery disease patients and coronary artery disease patients older than 75 years. Conclusion Lifelong preventive treatment of coronary artery disease and peripheral arterial disease patients at risk of cardiovascular events with dual pathway inhibition improves health outcomes and seems overall cost-effective relative to aspirin antiplatelet therapy and also to clopidogrel antiplatelet therapy for peripheral arterial disease, particularly in comorbid patients, but not in older patients and in carotid artery disease patients. These findings may warrant a targeted approach

Comparison of EQ-5D and SF-36 in untreated patients with symptoms of intermittent claudication

Aim: To compare health-related quality of life (HRQoL) descriptions and utility scores in newly diagnosed peripheral arterial disease (PAD) patients, using two most widely used instruments, EuroQol 5D (EQ-5D) and Medical Outcome Study 36-item Short-Form Health Status Survey (SF-36). Methods: Patients' self-assessment of HRQoL was measured by the Dutch versions of the EQ-5D and SF-36 in the 204 patients. Results: Mean utility scores ranged from 0.675 for Short-Form Six-Dimension, 0.648 for the EQ-5D UK tariff and 0.715 for the Dutch EQ-5D tariff. A moderate correlation between the utility scores was found due to different valuation techniques of these instruments. Conclusion: Both instruments have clinical validity for use in the PAD and can be used alongside each other to provide a holistic assessment of the HRQoL. Before using these two instruments interchangeably for utility score calculations and healthcare resource allocation, a thorough sensitivity analysis is necessary to explore the robustness of the value argument based on these utility scores

Comparison of three generic quality-of-life metrics in peripheral arterial disease patients undergoing conservative and invasive treatments

Purpose To determine the effect of revascularisation for peripheral arterial disease (PAD) on QoL in the first and second year following diagnosis, to compare the effect depicted by Short Form Six Dimensions (SF-6D) and EuroQoL five Dimensions (EQ-5D) utilities, and Visual Analogue Scale (VAS) scores and to analyse heterogeneity in treatment response. Methods Longitudinal data from 229 PAD patients were obtained in an observational study in southern Netherlands. Utility scores were calculated with the international (SF-6D) and Dutch (EQ-5D) tariffs. We analysed treatment effect at years 1 and 2 through propensity score-matched ANCOVAs. Thereby, we estimated the marginal means (EMMs) of revascularisation and conservative treatment, and identified covariates of revascularisation effect. Results A year after diagnosis, 70 patients had been revascularised; the EMMs of revascularisation were 0.038, 0.077 and 0.019 for SF-6D, EQ-5D and VAS, respectively (always in this order). For conservative treatment these were -0.017, 0.038 and 0.021. At 2-year follow-up, the EMMs of revascularisation were 0.015, 0.077 and 0.027, for conservative treatment these were -0.020, 0.013 and -0.004. Baseline QoL (and rest pain in year 2) were covariates of treatment effect. Conclusions We measured positive effects of revascularisation and conservative treatment on QoL a year after diagnosis, the effect of revascularisation was sustained over 2 years. The magnitude of effect varied between the metrics and was largest for the EQ-5D, which may be most suitable for QoL measurement in PAD patients. Baseline QoL influenced revascularisation effect, in clinical practice this may inform expected QoL gain in individual patients

Exploring the Feasibility of Comprehensive Uncertainty Assessment in Health Economic Modeling:A Case Study

Objectives: Decision makers adopt health technologies based on health economic models that are subject to uncertainty. In an ideal world, these models parameterize all uncertainties and reflect them in the cost-effectiveness probability and risk associated with the adoption. In practice, uncertainty assessment is often incomplete, potentially leading to suboptimal reimbursement recommendations and risk management. This study examines the feasibility of comprehensive uncertainty assessment in health economic models. Methods: A state transition model on peripheral arterial disease treatment was used as a case study. Uncertainties were identified and added to the probabilistic sensitivity analysis if possible. Parameter distributions were obtained by expert elicitation, and structural uncertainties were either parameterized or explored in scenario analyses, which were model averaged. Results: A truly comprehensive uncertainty assessment, parameterizing all uncertainty, could not be achieved. Expert elicitation informed 8 effectiveness, utility, and cost parameters. Uncertainties were parameterized or explored in scenario analyses and with model averaging. Barriers included time and resource constraints, also of clinical experts, and lacking guidance regarding some aspects of expert elicitation, evidence aggregation, and handling of structural uncertainty. The team's multidisciplinary expertise and existing literature and tools were facilitators. Conclusions: While comprehensive uncertainty assessment may not be attainable, improvements in uncertainty assessment in general are no doubt desirable. This requires the development of detailed guidance and hands-on tutorials for methods of uncertainty assessment, in particular aspects of expert elicitation, evidence aggregation, and handling of structural uncertainty. The issue of benefits of uncertainty assessment versus time and resources needed remains unclear